How James Webb’s MIRI Will Help Show The Universe In More Detail Than Ever Before

To see the detail MIRI is capable of, NASA has released a zoomed-in version of MIRI’s first image in a side-by-side comparison to an image from the previous flagship infrared telescope, the Spitzer Space Telescope. Spitzer, which was launched in 2003 and retired in 2020, had cutting-edge technology for its time and, like Webb, also looked at the infrared wavelengths. Compared to Webb, however, it was capable of far less detail.

In the comparison image, you can see the same target — a small satellite galaxy of the Milky Way called the Large Magellanic Cloud — taken by both telescopes. On the left is an image taken by Spitzer Space Telescope’s Infrared Array Camera, which operated at 8.0 microns. On the right is the image from MIRI, which operates at 7.7 microns. The sharper image makes it possible to see the target in greater detail and pick out more features of scientific interest.

“For example, Webb’s MIRI image shows the interstellar gas in unprecedented detail,” Alise Fisher of NASA writes. “Here, you can see the emission from ‘polycyclic aromatic hydrocarbons,’ or molecules of carbon and hydrogen that play an important role in the thermal balance and chemistry of interstellar gas. When Webb is ready to begin science observations, studies such as these with MIRI will help give astronomers new insights into the birth of stars and protoplanetary systems.”